Skipping DateTime::Format::Mail in the Pull Request Club
The reporter complained the module fails to parse the following e-mail header:
Date: Wed, 10 Jul 2019 11:20:02 +0200 (CEST)
I cloned the repository and briefly examined it. It’s based on Dist::Zilla, but running
worked for me without the need to call
dzil. I noticed a test named “sample.t” that took the largest part of the testing time and read its source. It read strings from a file and tried to parse each of them. I added the problematic string into the file and reran the test—only to find it still passed.
I replied to the bug report that I couldn’t reproduce the problem. Within few minutes, the reporter sent me the exact line that didn’t work for him:
perl -MDateTime::Format::Mail -e ' DateTime::Format::Mail->new->strict->parse_datetime("Wed, 10 Jul 2019 11:20:02 +0200 (CEST)")'
The important difference to what the test did was the
->strict method. It switches the parser object into a strict mode that is less tolerant than the loose mode used in the test. In this case, it’s the parenthesised time zone name that’s invalid: comments are forbidden in dates by the current standard.
As pointed out by PALI, one should use the loose method to parse incoming e-mail headers, so they don’t reject messages sent from old systems not conforming to the latest standards. When creating an e-mail header, though, you should switch to the strict mode, so you produce the header according the up-to-date specification.
DateTime::Format::Mail is a small module. I didn’t find anything else to work on, and as September was already over, I decided to skip the month. I don’t feel bad about it, though: I helped the module’s user and solved an open issue.